Method of galvanically treating metallic sectional bodies

ABSTRACT

Multipart sectional bodies, of metallic component sections, e.g., hollow sections for window and door frames formed of extruded aluminum sections, are provided with different surface layers, e.g., layers of different color, on the several sections in galvanic treatments by electrically insulating the sections from each other and galvanically treating the body in different baths while connecting only one of the component sections to a source of electric current while immersed in each bath.

United States Patent [191 Grune METHOD OF GALVANICALLY TREATING METALLIC SECTIONAL BODIES [76] Inventor: Heinz Grune, Schleifersberg l5,

Solingen, Germany [22] Filed: Dec. 1, 1971 [21] Appl. No.: 203,577

[30] Foreign Application Priority Data Dec. 9, 1970 Switzerland 18217/70 [52] US. Cl 204/15, 204/25, 204/56 R, 204/58 [51] Int. Cl...... C23b 11/00, C23b 9/02, C23b 5/48 [58] Field of Search 204/15, 198, 202, 204/25, 56 R, 58

[56] References Cited UNITED STATES PATENTS 3,324,015 6/1967 Saia et al. 204/15 Nov. 13, 1973 Primary ExaminerF. C. Edmundson Attorney-Cushman, Darby & Cushman [57] ABSTRACT Multipart sectional bodies, of metallic component sections, e.g., hollow sections for window and door frames formed of extruded aluminum sections, are provided with different surface layers, e.g., layers of different color, on the several sections in galvanic treatments by electrically insulating the sections from each other and galvanically treating the body in different baths while connecting only one of the component sections to a source of electric current while immersed in each bath.

8 Claims, 4 Drawing Figures Patented Nov .13, 1973 2 Shoots-Sheet 1 2 Sheets-Shoat 2 Fig.3

METHOD OF GALVANICALLY TREATING METALLIC SECTIONAL BODIES The present invention relates to a method of galvanically treating sectional bodies formed of metallic part sections. This invention further relates to sectional bodies obtained by this method.

Sectional bodies formed of metallic component sections are known and used in large number, by way of example as hollow sections for window and door frames. With such sectional bodies, which frequently consist of aluminium, it is at times desirable to provide the metallic outside surfaces of the whole sectional body with anodic oxidation or other surface layers to which end galvanic treatment of the type known is performed on the sectional bodies. In this manner the metallic outside surfaces of the sectional bodies may be provided with durable and, if desired, coloured surface layers.

For many applications it would be desirable anodically to oxidize the metallic component sections of such a sectional body in different ways in order to produce, by way of example, two-colour sectional bodies. For this purpose it has so far been necessary to provide part of the metallic outside surfaces of the sectional body with a protective coat prior to the galvanic treament or to cover the same with adhesive tape leaving only the free metallic surfacesfor anodic oxidation, then to remove such protection and to cover the anodically oxidized surface portions so as to perform a second galvanic treatment to oxidize the other metallic outside surfaces of the sectional body in a different manner. Such treatment of sectional bodies is costly and time-consuming so that e.g., two-colour aluminium hollow sections have to date been produced only rarely. I

The present invention relates to a substantially simpler method of galvanically treating sectional bodies of the type consisting of metallic component sections. Such sectional bodies formed of extruded or drawn component sections are at present used in major quantities. The present method is characterized in that seetional bodies are used with nonmetallic connecting members for preventing metallic contact between the component sections, that such sectional bodies are galvanically treated in a bath while one of the component sections is connected to the current source.

The sectional bodies obtained according to this method are characterized by a different surface of the component sections forming the sectional body.

A number of embodiments of the invention will now be described with reference to FIGS. 1 through 4 of the drawings in which FIG. I is a portion of a box-type hollow section consisting of two component sections in a diagrammatic perspective view;

FIG. 2 shows a galvanic bath for the treatment of a hollow section according to FIG. 1 in application of the present method, and

FIGS. 3 and 4 show further embodiments of sectional bodies.

The present method will now be described in conjunction with the embodiment of a sectional body in the shape of a box-type metallic hollow section according to FIG. 1 which is formed ofa box-type upper component section 100 and a second component section 101 forming the bottom surface. The longitudinal edges of the lower component section 101 are beaded up and enclose the longitudinal edges of the upper component section 100. Provided in the enclosing longitudinal edges, however, are nonmetallic separators 102 and 103, by way of example formed of an elastic plastic material, which prevent metallic contact between the component sections and 101. Such hollow sections formed of component sections insulated relative to one another are already known, e.g., from Swiss Pat. No. 454,414. I

With a hollow section of the design shown in FIG. 1 and formed of aluminium it is now desired, by way of example, to provide the entire outside surface of the lower component section 101 with a thin surface layer 135, e.g., by anodic oxidation in an appropriate galvanic bath. This is possible according to the present method without any masking of the outsides of the upper component section 100 if the galvanic treatment illustrated in FIG. 2.is performed so that only the lower component section 101 is connected to the positive terminal 136 of the current source 137 of which the negative pole 138 is connected to the metallic tank 139 for the galvanic bath 140. Accordingly only the surface of the lower component section 101 is under an anodic potential and undergoes anodic oxidation also termed anodization while the surface of the upper component section 100, which is electrically insulated relative to the current source 137, is not influenced. It may thus be ensured without the necessity of masking that, as shown in FIG. 1, only the outside of the lower aluminium component section 101 is provided with a surface layer which possesses a certain colour depending on the type of the galvanic bath 140 used.

As is well known, galvanic oxidation according to FIG. 2 may also be performed for certain purposes by the use of an alternating-current source.

If it is desired to anodize the outside surface of the upper component section 100 with another coloration, it is only necessary galvanically to treat the hollow section in an appropriate different bath after completion of the galvanic treatment of the lower component section while only the upper component section 100 is connected to the current. source.

As experience shows, the nonmetallic separators 102 and 103 are not attacked by the baths during galvanic treatment if a suitable elastic plastic material is em ployed. As is generally known, the hollow sections must be adequately cleaned after conclusion of each galvanic treatment in order to remove the bath liquid. In addition, the aftertreatment of the anodized surface commonly referred to as scaling is of advantage, by way of example by means of steam sealing in a steam atmosphere or by other suitable methods.

The present method is naturally applicable not only to hollow sections of the design shown in FIG. 1 but to all sectional bodies formed of metallic component sections and nonmetallic connecting members arranged between them so that no metallic contact is established between these component sections.

An embodiment of a further sectional body of this type is shown in cross-section in FIG. 3. The upper metallic component section 141 is here connected with the lower metallic component section 142 by means of a sectional bar 143 formed of a non-metallic material. Anchoring is effected by the attachment grooves here shown as having a triangular section which are provided on the opposite end faces 144 and 145 of the two component sections 141 and, respectively, 142.

The further embodiment of a sectional body shown in cross-section in FIG. 4 possesses an upper and a lower metal plate 146 and 147 with a connecting member 148 extending around the periphery of the two metal plates, here by way of example a plastic strip provided with grooves to accommodate the bent edges of the plates. The space 149 between the metal plates 146 and 147 is filled with a nonmetallic material, by way of example plastic foam, glass foam or the like. Sectional bodies of this type are suitable e.g., as curtain walls for buildings.

The present method may naturally be used for such sectional bodies of which the metallic component sections are formed of different metals. By way of example, it may be of advantage with a hollow section of the design shown in FIG. 1 to form the lower component section 101 of iron or steel while the upper component section 100 consists of aluminium. ln that case it is advantageous to treat the lower component section 101 in a galvanic bath pursuant to the present method and to provide it with a surface layer that protects it from rusting, by way of example with a copper or chromium layer. If desired, the component section 100 formed of aluminium may then be anodically oxidized in a second galvanic treatment as described above.

The present method is not limited to the anodic oxidation of component sections made of aluminium but enables any desired galvanic treatment to be given to the individual component sections, which are electrically insulated relative to one another, of a hollow section. The nonmetallic connecting members, intermediate layers and materials must be electrical insulators so that no metallic contact is established between the component sections.

1 claim:

1. The method of producing long hollow bodies with surface portions of different materials comprising the steps of:

producing a hollow body from at least two profiled channel-like rails made from metal by assembling them together with non-metallic electrical insulating separators which prevent electric contact between the said rails,

treating the assemblied hollow body in a galvanic solution by connecting an electrode to one terminal of a source of electrical current and one of the rails to the other terminal of said source,

maintaining a current flow between said electrode and said one rail for galvanically treating the outer surface of said one rail.

2. The method according to claim 1 in which the process is repeated in another galvanic solution in which the other of the rails is connected to the other terminal of said source of current.

3. The method according to claim 1 in which the rails are made of aluminum and the outer surface of said one rail is anodically oxidized.

4. The method according to claim 2 in which the rails are made of aluminum and the outer surface of both rails in anodically oxidized.

5. The method according to claim 1 in which the rails are made of different metals.

6. The method according to claim 1 in which the rails comprise at least one rail made of ferrous metal and this one rail is treated galvanically.

7. The method according to claim 1 in which the rails comprise at least one rail made of ferrous metal and this one rail is treated galvanically and provided with a rust-protection surface layer of copper or chromium.

8. The method of providing a double-walled body made from two metallic sheets with spacing members and an insulating filler within the body with surface portions of the walls of different material, comprising the step of:

producing said body with non-metallic electrically insulating spacing members and a non-metallic electrically insulating filler to prevent an electrical contact between the two metallic sheets,

treating the said body in a galvanic solution by connection of an electrode to one terminal of a source of electrical current and one of the said sheets to the other terminal of said source,

maintaining a current flow between said electrode and said one sheet for galvanically treating the outer surface of said one sheet. 

2. The method according to claim 1 in which the process is repeated in another galvanic solution in which the other of the rails is connected to the other terminal of said source of current.
 3. The method according to claim 1 in which the rails are made of aluminum and the outer surface of said one rail is anodically oxidized.
 4. The method according to claim 2 in which the rails are made of aluminum and the outer surface of both rails in anodically oxidized.
 5. The method according to claim 1 in which the rails are made of different metals.
 6. The method according to claim 1 in which the rails comprise at least one rail made of ferrous metal and this one rail is treated galvanically.
 7. The method according to claim 1 in which the rails comprise at least one rail made of ferrous metal and this one rail is treated galvanically and provided with a rust-protection surface layer of copper or chromium.
 8. The method of providing a double-walled body made from two metallic sheets with spacing members and an insulating filler within the body with surface portions of the walls of different material, comprising the step of: producing said body with non-metallic electrically insulating spacing members and a non-metallic electrically insulating filler to prevent an electrical contact between the two metallic sheets, treating the said body in a galvanic solution by connection of an electrode to one terminal of a source of electrical current and one of the said sheets to the other terminal of said source, maintaining a current flow between said electrode and said one sheet for galvanically treating the outer surface of said one sheet. 